Method for producing carbon nanofiber composite and carbon nanofiber composite

Abstract

A method for a carbon nanofiber composite, which can obtain a carbon nanofiber composite with high productivity and high activity, and which does not require removal of fluidizing materials or dispersing materials, provides a carbon nanofiber composite having improved dispersibility. The method for producing the carbon nanofiber composite includes bringing at least one catalyst and at least one particulate carbon material into contact with at least one gas containing at least one gaseous carbon-containing compound while mechanically stirring the catalyst and the particulate carbon material in a reactor. The carbon nanofiber composite includes carbon nanofibers and at least one particulate carbon material, wherein the particulate carbon material has 70% by volume or more of particles with a particle diameter of 1 μm or less, and/or a median diameter D50 by volume of 1 μm or less.

What is claimed is: 
     
       1. A method for producing a carbon nanofiber composite, comprising bringing at least one catalyst and at least one particulate carbon material as a fluidizing dispersant which imparts fluidity to the catalyst into contact with at least one gas containing at least one gaseous carbon-containing compound, while mechanically stirring the catalyst and the particulate carbon material in a state that the catalyst is fluid with respect to the particulate carbon material in a reactor, and
 wherein the particulate carbon nanofiber composite comprises 70% by volume and more of particles within (i) a particle diameter of 1 μm or less, and (ii) a median diameter D50 by volume of 1 μm or less. 
 
     
     
       2. The method for producing the carbon nanofiber composite according to  claim 1 , wherein the reactor comprises a rotary reactor. 
     
     
       3. The method for producing the carbon nanofiber composite according to  claim 1 , wherein the carbon nanofiber composite comprises 70% by volume or more of particles with a particle diameter of 1 μm or less, and a median diameter D50 by volume of 1 μm or less. 
     
     
       4. The method for producing the carbon nanofiber composite according to  claim 1 , wherein the particulate carbon material comprises one or more selected from graphite, carbon black, and graphene. 
     
     
       5. The method for producing the carbon nanofiber composite according to  claim 1 , wherein the gaseous carbon-containing compound comprises carbon monoxide. 
     
     
       6. The method for producing the carbon nanofiber composite according to  claim 1 , wherein the method comprises carrying out the reaction at a temperature ranging from 550° C. to 900° C. in the reactor. 
     
     
       7. The method for producing the carbon nanofiber composite according to  claim 1 , wherein the catalyst comprises one or more of the following (A), (B) and (C):
 (A) a catalyst in which an active species mainly based on cobalt is supported on a support comprising an oxide containing magnesium; 
 (B) a catalyst in which an active species mainly based on cobalt is supported on a support comprising an oxide containing titanium; and 
 (C) a catalyst in which an active species mainly based on any of iron and nickel is supported on a carbon particle support. 
 
     
     
       8. The method for producing the carbon nanofiber composite according to  claim 1 , wherein the method comprises allowing the gas containing the gaseous carbon-containing compound to flow such that the gaseous carbon-containing compound flows through the reactor at a flow rate of 0.1 NL/g-active species-minute or more. 
     
     
       9. The method for producing the carbon nanofiber composite according to  claim 1 , wherein the gas containing the gaseous carbon-containing compound further comprises hydrogen.